Attachment system

ABSTRACT

An attachment system for connecting a first member such as a lip plate ( 12 ) of a mechanical digging device to a second member such as a ground engaging tool ( 10 ). The first member has a lug ( 22 ) attached thereto, and the second member has a recess ( 50 ) which is located about the lug ( 22 ). A stabilizing member ( 98 ) is located within a slot ( 57 ) in the recess. A clamping member ( 60 ) is between the lug and the stabilizing member, and includes a resilient portion ( 90 ) such as a compression spring. A compressive force supplied to the resilient portion restricts the movement of the second member relative to the lug.

FIELD OF THE INVENTION

The present invention relates to an attachment system, particularlyintended for the attachment of ground engaging tools to the lip plate ofmechanical digging devices. Many mining and earthmoving operationsrequire the use of mechanical digging devices, such as front-endloaders. Such mechanical digging devices commonly feature buckets whichcan be manipulated by a user to dig into earth or rocks to be shifted.These buckets include a lip plate across the bucket floor. On this lipare mounted a series of ground engaging tools having a tooth-likeappearance. These tools, in use, penetrate into the material being dug,and provide a leading edge for the bucket to follow.

The ground engaging tools are highly susceptible to wear due to the highlevel of friction generated by their use. Accordingly, it is oftendesirable to be able to remove a worn ground engaging tool andsubstitute a new tool.

A common method of attachment for ground engaging tools is that ofwelding. In practice, however, a welded ground engaging tool can bedifficult to replace without substantial dismantling of the bucket.

Mechanical methods of attaching ground engaging tools through the use ofrestraining bolts and pins have been proposed. These methods are oftendifficult to use in practice, as the forces generated against a groundengaging tool can cause deformation of the bolt or pin, thus makingsubsequent disengagement difficult.

The present invention attempts to overcome at least in part some of theaforementioned disadvantages of previous attachment system for groundengaging tools.

SUMMARY OF THE PRESENT INVENTION

In accordance with one aspect of the present invention there is providedan attachment system for connecting a first member to a second member,characterised in that the first member has a lug connected thereto, thesecond member has an recess which receives the lug in use, and wherein aclamping member is disposed between the lug and the second member, theclamping member including a resilient portion such that the supply of acompressive force to the resilient portion acts to restrain movement ofthe second member relative to the lug.

In accordance with a second aspect of the present invention there isprovided an attachment system for connecting a first member to a secondmember, characterised in that the first member has a lug connectedthereto, the second member has an recess which receives the lug in use,the recess including a slot arranged to receive a stabilizing member,and wherein a clamping member is disposed between the lug and thestabilizing member such that the supply of pressure to the clampingmember acts to restrain movement of the second member relative to thelug.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a ground engaging tool arranged to beattached to a lip plate (a portion of which is shown) in accordance withthe present invention;

FIG. 2 is perspective view of the underside of the ground engaging toolof FIG. 1;

FIG. 3 is a perspective view of the ground engaging tool and lip plateportion of FIG. 1, shown during attachment, together with a clampingmember in accordance with the present invention;

FIGS. 4 to 8 are sequential cross sectional views of a portion of theground engaging tool and lip plate of FIGS. 1 to 3 during the attachmentprocess.

DESCRIPTION OF THE INVENTION

Referring to the Figures, there is shown a ground engaging tool 10arranged to be attached to a portion of a lip plate 12. The lip plate 12is substantially rectangular in cross section, and extends around therim of a bucket (not shown) of a mechanical digging device. The lipplate 12 includes an upper face 14, a lower face 16 and an end face 18.A tapered surface 20 extends from the end face 18 of the lip plate 12 tothe upper face 14.

The lip plate 12 includes a lug 22 affixed by suitable means to theupper face 14. In the embodiment shown in the drawings the lug 22 isaffixed by a weld 31. The lug 22 is oriented towards the end face 18 ofthe lip plate 12, and includes a top surface 26 which curves upwardly ina convex fashion from a first end of the lug 22 adjacent the taperedsurface 20 to a second end of the lug 22 remote from the tapered surface20.

The lug 22 further includes a substantially flat rear face 30 at thesecond end of the lug 22, the rear face 30 extending from the topsurface 26 to the upper face 14, and being substantially perpendicularto the upper face 14 and parallel to the end face 18.

The lug 22 has a side wall 24 which extends about the lug 22 and isbordered by the upper face 14, the top surface 26 and the rear face 30.

The ground engaging tool 10 comprises a leading edge 32, a first baseportion 34 extending substantially perpendicularly of the leading edge32, a front portion 36 extending away from the leading edge at a shallowangle, a second base portion 38 extending away from the first baseportion 34 at a shallow angle, a transverse recess 40 disposedoppositely the leading edge 32 and an attachment portion 42. The frontportion 36, leading edge 32 and the first base portion 34 co-operate toform a substantially V shaped working portion in order to penetrate, inuse, the material being dug. The transverse recess 40 is complementaryin shape to the lip plate 12, and allows the ground engaging tool 10 tobe located on the perimeter of the lip plate 12 adjacent the end face18. The second base portion 38 tapers from the first base portion 34 ina direction away from the leading edge 32, and ends, in use, adjacentthe lip plate 12. The leading edge 32, first and second base portions 34and 38 and the front portion 36 define a working portion of the groundengaging tool 10.

The attachment portion 42 extends from the front portion 36 adjacent therecess 40 in a direction away from the leading edge 32. It locates, inuse, along the upper face 14 of the lip plate 12, and co-operates withthe lug 22.

The attachment portion 42 has a substantially flat lower surface 44, asubstantially flat upper surface 46 and a rear surface 48. Theattachment portion 42 includes an engaging recess 50 extending inwardlyof the rear surface 48 through a rear aperture 52 in the rear surface48, and upwardly of the lower surface 44 through a lower aperture 45.The engaging recess 50 has a first portion 54 remote from the rearaperture 52, and a second portion 56 adjacent the rear aperture 52. Thefirst portion 54 is complementary in shape to the lug 22, whereas thesecond portion 56 has substantially constant cross section. The secondportion 56 is in the shape of a radiused rectangle in cross section, andis slightly larger in dimension than the rear face 30 of the lug 22.This allows, in use, the second portion 56 to be placed about the lug22. This in turn allows the attachment portion 42 to be slid over thelug 22 in a longitudinal direction, and to locate in a position wherebythe lug 22 is within the first portion 54 of the engaging recess 50. Inthis position relative movement of the attachment portion 42 and the lipplate 12 in a transverse direction is restricted.

The attachment portion 42 further includes a rectangular slot 57 whichextends from an aperture 58 within the upper surface 46 to the lowersurface 44. The rectangular slot 57 is arranged in a transversedirection, and is located within the second portion 56 of the engagingrecess 50. The rectangular slot 57 is larger in the transverse directionthan the second portion 56, and therefore forms a groove on either sideof the second portion 56. The aperture 58 communicates with the secondportion 56 of the engaging recess 50.

The attachment system further includes a clamping member 60. Theclamping member 60 is shown in FIGS. 3 to 8.

The clamping member 60 is of complementary cross sectional shape to thesecond portion 56 of the engaging recess 50 and has a first side 64which is arranged to locate adjacent the lug 22 and a second side 66opposite the first side 64. The second side 66 is arranged to locateadjacent the rectangular slot 57. The clamping member 60 furtherincludes side surfaces 67 and a top surface 68.

The clamping member 60 includes a substantially cylindrical chamber 80extending within the clamping member 60 from the first side 64 to a rearwall 82.

The clamping member 60 further includes a substantially cylindrical lugengaging member 62. The lug engaging member 62 is substantiallycomplementary in shape to, and contained within, the chamber 80. Anouter portion 63 of the lug engaging member 62 extends from the firstside 64 of the clamping member 60.

A resilient annular member such as an O-ring 65 is located within angroove about the chamber 80 adjacent the first side 64 of the clampingmember 60.

The lug engaging member 62 includes a substantially cylindrical recess81 extending inwardly of the lug engaging member 62 from a rear end ofthe lug engaging member 62 adjacent, in use, the rear wall 82 of thechamber 80.

A resilient portion 90 such as a compressible spring is located withinthe recess 81. In the embodiment of the drawings the resilient portion90 comprises a plurality of Belleville type cylindrical washers, howeverit will be appreciated that other resilient elements such as coilsprings, rubber or resilient plastic elements could be used.

A substantially cylindrical slot 110 extends from the chamber 80adjacent a rear end of the lug engaging member 62 to the second side 66of the clamping member 60. The slot 110 is internally threaded.

The attachment system further includes a stabilizing member 98. Thestabilizing member 98 is in the form of a prism, having front and rearfaces 100, 102. The stabilizing member 98 is substantially the sameshape as the rectangular slot 57.

The stabilizing member 98 has a substantially cylindrical aperture 112which is arranged to locate, in use, adjacent the slot 110 of theclamping member 60 so as to form a single cylindrical passageway. Thecylindrical aperture 112 may be threaded.

A compressing member in the form of a substantially cylindrical bolt 114is arranged, in use, to locate within the passageway formed by the slot110 and the aperture 112.

The bolt is externally threaded, and is arranged to engage with theinternally threaded slot 110. The bolt acts to hold the stabilizingmember 98 relative to the clamping member 60 during use. It will beappreciated that other means may be used to provide a compressive forcesuch as a hydraulically operated piston.

The use of the clamping member 60 will now be described.

The attachment portion 42 is positioned over the lip plate 12 with thelug 22 located within the first portion 54 of the engaging recess 50.This is shown in FIG. 4.

The clamping member 60 is then introduced through the rear aperture 52and slid forward relative to the attachment portion 42 until the firstside 64 is adjacent the rear face 30 of the lug 22, and the clampingmember 60 is free of the rectangular slot 57.

This is shown in FIG. 5.

The stabilizing member 98 is then introduced into the aperture 58, andpositioned in the rectangular slot 57 between the second side 66 of theclamping member 60 and the rear aperture 52. The presence of thestabilizing member 98 in the slot 57 prevents the movement of theclamping member 60 in the longitudinal direction. This is shown in FIG.6.

The clamping member is activated as follows. The bolt 114 is introducedinto the passage created by the slot 110 and the aperture 112, and isthreadedly engaged with the slot 110. When the bolt 114 is fully withinthis passage, the end of the bolt 114 is adjacent the resilient portion90. The application of a turning force to the bolt so as to promote theadvance of the bolt into the recess 81 provides a compressive force onthe resilient portion 90. This is shown in FIG. 7.

The effect of the compressive force on the resilient portion 90 is tocause lug engaging member 62 to apply a compressive force against therear face 30 of the lug 22. In this way a compressive force is appliedbetween the lug 22 and the attachment portion 42, thus locking theground engaging tool 10 in position relative to the lip plate 12. Thisfinal position is shown in FIG. 8.

When it is desired to remove the ground engaging tool 10 from the lipportion 12, the bolt 114 is unscrewed from the slot 110, thus releasingthe compressive force from the resilient portion 90 of the lug engagingportion 62. The attachment portion 42 can then be readily removed fromthe lip portion 12 in the reverse of the above process, potentiallyallowing some members to be reused.

Modifications and variations as would be apparent to a skilled addresseeare deemed to be within the scope of the present invention. Forinstance, the resilient portion 90 may be located externally of therecess 81.

1. An attachment system for connecting a lip plate of a digging deviceto a ground engaging tool, comprising: a lug mounted on the lip plateand including a rear face; an engaging recess arranged in a rearwardlyextending attachment portion of the ground engaging tool, extendinginwardly of the attachment portion from a rear surface thereof, theengaging recess being arranged to received the lug; a lug engagingmember insertable into the engaging recess from the rear surface of theattachment portion, the lug engaging member arranged to engage the rearface of the lug; a clamping member arranged to be receivedlongitudinally in the engaging recess, the clamping member comprising asubstantially cylindrical chamber housing the lug engaging member; aresilient member coupled to the lug engaging member opposite the lug;and a compressive member at least partially insertable into the engagingrecess from the rear surface of the attachment portion to apply acompressive force to the resilient member to engage the lug engagingmember with the rear face of the lug and restrain a longitudinalmovement of the lug relative to the ground engaging tool.
 2. Anattachment system according to claim 1, wherein the clamping membercomprises a front wall and an outer portion of the lug engaging memberextends outwardly from the front wall.
 3. An attachment system accordingto claim 1, wherein the substantially cylindrical chamber comprises arear wall arranged to received the compressive force through an aperturearranged on the rear wall.
 4. An attachment system according to claim 1,wherein the lug engaging member comprises a substantially cylindricalrecess extending inwardly from a rear end thereof, wherein the resilientmember is mounted in the substantially cylindrical recess of the lugengaging member.
 5. An attachment system according to claim 1, whereinthe lug engaging chamber comprises a rear wall including a slot, the lugengaging chamber being arranged to receive the compressive force throughthe slot, the slot being internally threaded and arranged to receive athreaded bolt, the bolt being threadably engaged within the slot toapply compressive force to the resilient member upon application of aturning force to press the lug engaging member into engagement with thelug.
 6. An attachment system according to claim 1, further comprising astabilizing member arranged to prevent an outward longitudinal movementof the clamping member.
 7. An attachment system according to claim 6,further comprising an aperture extending from an upper surface of theattachment portion and communicating with the engaging recess, whereinthe stabilizing member is insertable through the aperture into theengaging recess to engage with the clamping member, thereby preventingoutward longitudinal movement of the clamping member from the engagingrecess.
 8. An attachment system according to claim 7, wherein an innerwall of the engaging recess is grooved.
 9. An attachment systemaccording to claim 7, wherein the stabilizing member comprises a secondaperture arranged in alignment with the aperture.
 10. An attachmentsystem according to claim 1, wherein the engaging recess comprises: anopen lower end; a first portion remote from the rear surface of theattachment portion, the first portion being complementary in shape tothe lug to receive the lug; and a second portion adjacent the rearsurface of the attachment portion, the second portion having asubstantially constant cross section of slightly larger dimension thanthe lug to be placed about the lug to restrict a lateral relativemovement of the ground engaging tool and the lip plate.
 11. A groundengaging tool for connection to a lip plate, the lip plate including alug mounted thereon, the ground engagement tool comprising: a rearwardlyextending attachment portion having a rear surface and containing anengaging recess extending inwardly of the attachment portion from therear surface, the engaging recess being arranged to received the lug; alug engaging member insertable into the engaging recess from the rearsurface of the attachment portion, the lug engaging member arranged toengage a rear face of the lug; a clamping member arranged to be receivedlongitudinally in the engaging recess, the clamping member comprising asubstantially cylindrical chamber containing the lug engaging member; aresilient member coupled to the lug engaging member opposite the lug;and a compressive member at least partially insertable into the engagingrecess from the rear surface of the attachment portion to apply acompressive force to the resilient member to engage the lug engagingmember with the rear face of the lug and restrain a longitudinalmovement of the lug relative to the ground engaging tool.
 12. A groundengaging tool according to claim 11, wherein the clamping membercomprises a front wall and an outer portion of the lug engaging memberextends outwardly from the front wall.
 13. A ground engaging toolaccording to claim 11, wherein the substantially cylindrical chambercomprises a rear wall arranged to received the compressive force throughan aperture arranged on the rear wall.
 14. A ground engaging toolaccording to claim 11, wherein the lug engaging member comprises asubstantially cylindrical recess extending inwardly from a rear endthereof, wherein the resilient member is mounted in the substantiallycylindrical recess.
 15. A ground engaging tool according to claim 14,wherein the lug engaging chamber comprises a rear wall including a slot,the lug engaging chamber being arranged to receive the compressive forcethrough the slot, the slot being internally threaded and arranged toreceive a threaded bolt, the bolt being threadably engaged within theslot to apply compressive force to the resilient member upon applicationof a turning force to press the lug engaging member into engagement withthe lug.
 16. A ground engaging tool according to claim 11, furthercomprising a stabilizing member arranged to prevent an outwardlongitudinal movement of the clamping member.
 17. A ground engaging toolaccording to claim 16, further comprising an aperture extending from anupper surface of the attachment portion and communicating with theengaging recess, wherein the stabilizing member is insertable throughthe aperture into the engaging recess to engage with the clampingmember, thereby preventing outward longitudinal movement of the clampingmember from the engaging recess.
 18. A ground engaging tool according toclaim 17, wherein an inner wall of the engaging recess is grooved.
 19. Aground engaging tool according to claim 17, wherein the stabilizingmember comprises a second aperture arranged in alignment with theaperture.
 20. A ground engaging tool according to claim 11, wherein theengaging recess comprises: an open lower end; a first portion remotefrom the rear surface of the attachment portion, the first portion beingcomplementary in shape to the lug to receive the lug; and a secondportion adjacent the rear surface of the attachment portion, the secondportion having a substantially constant cross section of slightly largerdimension than the lug to be placed about the lug to restrict a lateralrelative movement of the ground engaging tool and the lip plate.